In the early 1940s, as Katherine Inglestone, Blake was a member of the Amersham Playhouse repertory company. In September 1941, she was a waitress in ''The Devil's Advocate
and in October played a ghost in A Murder Has Been Arranged''. In March and April 1942, she was Frau Rothmann in
Maurice Edelman's
Inheritance of Earth, billed as "a drama of the Struggle for Freedom". In February 1944, Blake returned to the Amersham Playhouse, still using her maiden name, in a production of
Spring Meeting. In 1948, when reporting her first television appearance, the local newspaper noted her as "Katherine Blake whom Amersham audiences will remember as Katherine Inglestone". In November 1946, under the new name of Blake, she played the part of Iras, a maid of honour, in a production of
Antony and Cleopatra at
Stratford-upon-Avon which by late December was in the West End at the
Piccadilly Theatre, with
Edith Evans playing Cleopatra and
Godfrey Tearle Mark Antony, and the play had a good run there. In March 1947, Blake was profiled with Evans and Tearle in
The Queen. In March 1948, she appeared as
Catherine Earnshaw opposite
Kieron Moore as Heathcliff in an early
BBC television adaptation of
Wuthering Heights, with
Patrick Macnee as
Edgar Linton. In 1949, Blake had another early screen appearance in
Trottie True. Between 1952 and 1959, she worked in Canada and the United States and was
naturalized as a Canadian citizen. In 1959, she returned to England. Blake won the
British Academy Television Award for Best Actress for her work in television in 1964. In 1969/1970 she played the character Chris Nourse in first an episode of
Public Eye and then in
Armchair Theatre's ''Wednesday's Child''; one of the first lesbian love affairs to be seen on British television. Blake replaced
Googie Withers as the Prison Governor in the ITV series
Within These Walls in 1977, but only appeared in one season, leaving the role due to ill health. Blake was also an occasional scriptwriter. ==Personal life==